Irritatingly, in SharePoint Meeting Workspaces have a different master page to most sites (mwsdefault.master and default.master respectively). The differences are actually quite minor – the Meeting has a ‘Custom Tool Pane’ control, so you can add new pages, and a tab bar:
In the code, the pages are very similar, which makes it all the more irritating that they’re not simply the same. As far as I can see, there is no need for this – at least, nothing that can’t be dealt with by content placeholders – which is what they’re using to get rid of the left navigation. Anyway, I digress – the real question is can we customise them, and provide consistent branding on them?
Meeting Workspaces use
MasterPageFile="~masterurl/custom.master"
in their Page directive, which is replaced at runtime with the site’s CustomMasterURL -typically this is:
<path to site>/_catalogs/masterpage/MWSDefault.master
The meeting workspace’s MasterURL property normally still points to :
<path to site>/_catalogs/masterpage/default.master
Note that this is rather against the MSDN remarks about CustomMasterURL, which say that these two properties must be the same!
So, can we customize them? Yeah, no reason why not – either, edit the MWSDefault.master for a site in place (yuck) or create a feature to deploy a new master page and set the CustomMasterURL in code, similar to what I’ve done before with team sites.
Hmm. All of this ‘two master page properties’ thing looks a lot like publishing pages.
Andy Burns' Blog 
[…] yesterday I was wondering about custom master pages for Meeting Workspaces. I found that Meeting Workspaces use their own master page (mwsdefault.master), which is referred […]
An improved SharePoint Meeting Workspace template can be downloaded here:
http://www.layer2.de/en/products/Pages/SharePoint-Meeting-Manager.aspx
It offers a more complete SharePoint meeting life-cycle management, e.g.
– automatic WordML template-based meeting minutes,
– additional lists, libraries and fields to centrally manage meeting materials
– role-based permissions for organizer, attendees and minute takers
– consistent management in Outlook and/or SharePoint
– improved notification and workflow system
– improved compliance
Just check it out!
Cheers, Frank
Well, it’s a commercial product, but that’s much more like the feature set I’d like to see from the meeting workspace. And I’d like it to use the same Master page as ordinary sites. Any word on that?
I mean, sure, OVERRIDE default.master’s standard content for the left nav, etc.. But a second master page is an annoyance.